


A Martian Stole My Body!

by doctornerdington



Category: Sherlock (TV)
Genre: 1950s, Alternate Universe - Science Fiction, Bodyswap, M/M, Pastiche, Pseudoscience, Pulp Science Fiction
Language: English
Status: Completed
Published: 2020-09-17
Updated: 2020-09-17
Packaged: 2021-03-06 22:35:53
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 14,309
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26176561
Author URL: https://archiveofourown.org/users/doctornerdington/pseuds/doctornerdington
Summary: "I don't know why you would believe me, but by God you're the only person to really listen to me since this whole nightmare began," the strange creature whispered urgently to Sherlock Holmes. "I think I must be mad, but I must try to make you understand! My name is John Watson, and a Martian has stolen my body."
Relationships: Sherlock Holmes/John Watson
Comments: 20
Kudos: 42





	A Martian Stole My Body!

**Author's Note**

To all profound thinkers in the realms of Science who may chance to read this tale, greetings:

I have taken certain liberties with several more or less commonly accepted theories, but I assure you that those theories have not been violated altogether in ignorance. Some of them I myself believe sound, others I consider unsound, still others are out of my line, so that I am not well enough informed upon their basic mathematical foundations to have come to any definite conclusion, one way or the other. Still, it is my belief that there is no scientific impossibility to be found herein.

Please bear in mind that we _know_ very little. We do not know the nature of light. Neither the undulatory theory nor the quantum theory are adequate to explain all observed phenomena, and they seem to be mutually exclusive, since it would seem clear by definition that no one thing can be at the same time continuous and discontinuous. We know nothing of the ether--we do not even know whether or not it exists, save as a concept of our own extremely limited intelligence. We are in total ignorance of the ultimate structure of matter, and of the arrangement and significance of those larger aggregations of matter, the galaxies. We do not know nor understand, nor can we define, even such fundamental necessities as time and space.

Why talk of "the impossible"? The universe is so much larger than we humans can comprehend.

Doctor Nerdington

1952

*****

_Our story opens in the labyrinthine underground corridors of Diogenes Laboratories one cold and drizzly February night in London. A whispered conversation echoes guiltily down the otherwise silent halls..._

"It must be a hoax of some kind."

"A palpable hoax."

"How the thing could be done, I can't imagine. And yet –"

"And yet. You've seen it. You've _heard_ it."

"Well sure, but... Twelve years I've worked here, and I've never seen anything like it."

"I know. And how do you explain the –"

A familiar clatter in the hall made the maintenance men pause their conversation. Sherlock Holmes, self-proclaimed "consulting xenophysicist," rushed past them without a glance. He had a reputation for ill temper, and they knew better than to get in his way. As soon as he'd disappeared around the corner, they relaxed against the wall, relighting their cigarettes.

"It's just got to be a hoax..."

*****

Meanwhile, in the innermost private office in the inner sanctum of the laboratory – often simply called "the Club" for its exclusivity and air of luxurious opulence – Mr. Mycroft Holmes and his security chief Gregory Lestrade stared at each other across a massive oak desk. Holmes's voice was cold, his mouth pressed into a thin line.

"Absolutely not," he was saying. "I'm leaving at eight o'clock tonight. I have other responsibilities that I can no longer neglect. My advice to you is to do the same. Nothing else! _Nothing_. Hold everything. Keep on holding it until I get back, no matter how long that may be." In an icy tone, he added, "Stop asking questions and just – do the job you were hired to do. I don't pay you for your opinion."

Lestrade flinched, as if slapped. "You don't care to inform me more fully as to your plans?"

"I do not. Any further information is far above your pay grade."

At that, Lestrade eyed him sharply. He'd worked for the man long enough -- and knew him well enough -- to ignore the small insult and speak instead to its cause. "I am very much surprised at your change of mind, sir," he replied. "You're the last man I would have expected to be frightened off after one engagement."

Mycroft raised an eyebrow. "Don't be ridiculous. There's a vast difference between being 'frightened off,' as you say, and knowing when you are simply wasting effort. As you remember, I tried previously to ... engage ... on more than one occasion, and without meaningful success."

"That's because you're going about it all wr--. You're not considering the full range of methods open to you. _Sir_." Lestrade's frustration was becoming evident, though he strove to bite it back.

Holmes's frown deepened. "I suppose we should try more of your methods, then, should we? Conversation? _Psychology_?" He spat out the last word as if it had a bitter taste. "This situation has the potential to develop into a serious threat to national – to _global_ – security, Lestrade, and if you pull any more of your fool ideas..."

The man made no reply other than a gesture of resignation.

"None of your ideas have worked," Mycroft Holmes continued. " _None_ of them. I've drawn you diagrams and shown you figures--I've told you in great detail and in single-syllable words exactly what we're up against. Now I tell you again to simply leave it alone. My way is absolutely the only way that will both mitigate potential risks and allow for the possibility of benefit to us."

Lestrade shook his head sharply. "You stand just as much chance of killing it with these 'examinations' as learning anyth--"

"Termination is not our current objective," Mycoft Holmes interjected smoothly, relenting slightly, "but nor is it outside the bounds of possibility. Such an event would be regrettable, certainly, but it would at least remove all possibility of interference by competing influences."

"And what about the science of it?" Lestrade asked, desperately playing his last card. "Dr. Hooper says that nine-tenths of it, at least, is scientifically impossible. _We don't even know what it is_. Can you afford to destroy such a treasure trove of scientific – no, of tactical – importance?"

"Lestrade," Holmes sighed, and suddenly he looked almost sad. "I have no wish to do it harm. But there may come a time when we can't afford not to. You must prepare yourself."

*****

Sherlock Holmes swept into the experimental xenophysics wing of Diogenes Laboratories and crushed the cigarette he'd been smoking furiously under his heel.

"Hooper!" he bellowed, planting himself in front of a messy desk in the centre of the workspace.

A small, timid woman hurried over, her expression apprehensive. "Oh, Sherlock!" she said breathlessly. "I wasn't expecting you in tonight."

"I'm sure you weren't. Had some private work to do, did you? Something you didn't want me to know about?"

Dr. Molly Hooper blushed crimson, but said nothing.

"I see. You've been holding out on me," Sherlock continued. "I wonder why? What on earth could be so confidential that you couldn't even talk to _me_ about it...?"

"Sherlock--please," she stammered. Even after years of acquaintanceship, he had a way of unnerving her. "I don't know how you've found out, but the project is full-alpha classified. I could lose my job; he made that very clear. Lose my job if I'm lucky! Gaol time, more like, blabbing about state secrets. He'd lock me up in a heartbeat, and throw away the key! I couldn't--"

"Stop. Boring. Don't care. _Obviously_ he's not going to fire the best xenobiologist in the country. You're far too valuable, especially now. But no matter! I've been tipped off by other sources, so your conscience is perfectly clear. You didn't tell me. You don't know who did. All you need to do is put your files on your desk for a few hours and leave me alone."

Molly bit her lip. She had no desire to break her promise of secrecy to Mycroft Holmes who, despite his exquisite manners, was quite the most terrifying man she'd met. On the other hand, Sherlock was a brilliant scientist--the most astonishing mind she'd encountered. And the truth was, she was stuck.

Mycroft had called her in to consult on this special case--the most exhilarating of her career--on the sole condition that she not involve his brother. And here he was, planted in the middle of her lab and looking unlikely to shift.

She'd been working on the project around the clock for over a week -- since it had all begun, really--and she was no further ahead than she'd been at the beginning. She was exhausted and intensely frustrated. She had little use for the fraternal idiocy of the Holmes brothers at the best of times, and in this case, it seemed needlessly obstructive to thwart Sherlock any further. He was right. If Mycroft protested, she could legitimately claim innocence. She certainly hadn't called him in, at any rate. She wondered, for a moment, who had.

"Alright," she said finally. "You know I'm not supposed to leave you alone in the lab, but I'm exhausted and I want a coffee. I'm putting my files down here, and I'll return in 45 minutes. That's all I can do, Sherlock. You'd best not be here when I get back."

Sherlock jumped up, rubbing his hands together in glee. "Molly, you're an angel! Here--" he tossed her a little key. "Cake with your coffee tonight. You know the cupboard where Mycroft hides the good stuff."

Molly smiled in spite of herself. She and Sherlock had had their ups and downs over the years. She'd even quite fancied him once, God help her. But they'd reached a pattern of interaction that was beginning to feel almost like a friendship, if a strange one, and Molly was glad with all her heart that Sherlock wasn’t holding a grudge against her now.

She was still smiling faintly when she left the lab.

* * * * *

Sherlock wasn't gone when she returned, of course. She hadn't really imagined that he would be -- not with a case like this on offer. He pounced on her the instant she set foot through the door.

"Where is it?" he demanded, grabbing her shoulders and giving her a little shake. " _Where_?"

She shook her head. "You'll never get in. It's in Mycroft's private lab. He won't even let me near it unless he's there to personally supervise."

He growled with frustration. Mycroft alone held the key to his private lab. Well, Mycroft and his lackey...

"We need to find Lestrade," he said, straightening up at once. "Where is he usually at this time of night?"

"Why...? Why do you think I'd know where G-- where Mr. Lestrade is?" Molly asked, again flushing.

Sherlock rolled his eyes, then grabbed for the 'phone that sat on her desk. He entered a complicated series of codes, and the speaker mounted near the ceiling of the lab crackled to life, as did all the speakers in the facility simultaneously.

"Giovanni Lestrade, report to the Experimental Xenophysics Lab. Giovanni to Experimental Xenophysics immediately."

Molly giggled despite herself. "That should do it."

Two floors below them, Gregory Lestrade heaved an aggrieved sigh and downed the last of his coffee. He'd wondered how long it would take for Sherlock Holmes to receive his anonymous tipoff. His life, he reflected wryly, had just got a lot more complicated. 

* * * * *

The instant Greg Lestrade arrived in the lab, Sherlock leapt to his feet. "Ah! Gilderoy! You've arrived. How slow you are! But no matter. I require access to room MH439, if you would be so kind?" 

Lestrade shook his head in wonder. "Now, hang on, Sherlock. You know I can't open up Mr. Holmes's personal lab just... on your say-so. It's more than my--"

"More than your job is worth, yes, yes. It doesn't matter."

"Doesn't _matter_? It does to me. Matters quite a lot, in fact."

Molly nodded vigorously.

Sherlock groaned and pulled at his hair. He then spoke rapidly: "I received an anonymous tip through my janitorial information network that my brother is working on something--big. Having seen facility notes on the situation, I now require firsthand experience of the, er, specimen in question. Given that there is an 87.3% chance that one of you two is in fact the anonymous source" -- here, Greg shifted slightly on his feet and Sherlock shot him a sharp glance -- "I'd suggest you pull yourselves together and _stop wasting my time_!"

Molly and Greg glanced at each other. Molly raised her eyebrows, questioningly.

He smiled slightly in return.

"Oh, for heaven's sake!" Sherlock exclaimed. "Do you wish for my help? Or shall I leave? Don't waste my time with this ridiculous shilly-shallying. I must see it. I must!" He all but stamped his foot.

Lestrade smiled more broadly. "Temper, Sherlock! Do you want me to help you, or not?"

Sherlock was silent.

"That's better. Goodness! I don't know why I put up with you," Lestrade said.

"You need me, and you know it," Sherlock said haughtily. "If this -- this case -- is everything it seems to be, you'll need all the help you can get."

Greg sighed. He knew it was true. He was conflicted about going behind Mycroft's back like this, but the man was being recklessly, dangerously stubborn. More than that, he was being uncharacteristically cruel, and Lestrade had reached the end of his tolerance. "Come on then," he said at last. "Mr. Holmes is out for the rest of the night. I can't let you in myself, but here, you can pickpocket me. It's a marvel you didn't in the first place. There. You'll have a few hours alone with it. But listen -- don't hurt it, will you? It needs -- _he_ needs -- our help."

"Mmm, I'll be sure to take your professional opinion as a hired lacky under advisement," Sherlock said, stepping past him into the darkened hallway beyond.

*****

Sherlock strode into his brother's lab, darkened for the night, switching the lights to full brilliance as he went. It was exquisitely equipped, as any workplace occupied by Mycroft Holmes must surely be. State of the art scientific equipment lined the gleaming benches that ran the full length of the spacious room, more specialized and far more modern than any official government lab in the country—perhaps in the world.

Running the full length of the back of the lab was a floor-to-ceiling, transparent aluminium oxynitride window. He hesitated briefly before switching on the lamps in the observation chamber, as well.

"Oh, good. Another lab-coat come to poke at me."

Sherlock nearly jumped out of his skin. He had known the specimen -- the creature, he supposed -- could speak, of course. He'd read the reports in Molly’s files. But somehow knowing that fact and actually hearing it speak – speak _English_ , at that, in a perfectly human male, ordinary, British sort of voice – was profoundly shocking. The evidence of his eyes told him one thing: told him that this was something foreign – something incomprehensibly other. But the evidence of his ears said something quite different, and the experience of such dissonance made him unsettled, almost dizzy. He shook his head. He'd been declaiming the possibility of similar phenomena for years -- since he was sent down by the idiots in Oxford, in fact -- but only theoretically, as a thought experiment more than anything else. The instant he’d heard of the creature's discovery, and of his brother's execrable treatment of it, he'd been desperate to see it.

He took up his clipboard and his satchel of instruments and walked to the plexiglass wall that divided the room into two identical halves: white, sterile, empty, neatly separating observer and observed. The only difference, Sherlock reflected, was that his side had a door through which he had the freedom to depart at any time. The creature had no such escape.

"My name is Holmes. Sherlock Holmes," he said, as brightly as he could. "And if you tell me your name, I'll promise not to poke at you at all."

"Fuck off," the creature said. It hadn't moved from where it slumped against the far wall of its cell. It – _he?_ – sounded more tired than angry, Sherlock thought. "You all say you won't hurt me. You all promise to help me. You all –. Well. You know what you do to me."

"Excuse me, but I know no such thing. I've not done anything to you at all, except to introduce myself. I have never seen you before this moment. Anything that has hurt or harmed you previously has been the express purview of the cretins that my lazy pig of a brother keeps on his staff--and I'll thank you not to lump me into the same category as them."

There was a sound like metal rubbing against stone from the creature. Sherlock had no idea what it meant. It was infuriating to be so entirely clueless. It was _breathtaking_.

"Visual inspection," he chided himself under his breath. He was no green junior tech, he was Sherlock Holmes – the greatest consulting xenophysicist in the world! (Admittedly also the only one, but he knew himself to be extraordinarily brilliant, regardless.) He turned the full power of his observational faculties on the creature before him, taking careful notes all the while.

It was humanoid in form, Sherlock was relieved to see, although slightly larger than the human baseline. His theory on ideal evolutionary forms for creatures of higher intelligence had, at least, been correct. The files he'd obtained from Molly listed the creature's height (almost 7 feet), weight (an astonishing 57 stone; it must be very dense), measurements, temperature, and respiration rates: resting and stressed. Attempts to x-ray it had proved futile, as had all efforts to extract blood or other fluids. Its skin -- a smooth, flat expanse of garish red that was reportedly both as hard as marble and as flexible as rubber -- seemed impervious to penetration of any kind. Sherlock squinted, trying to ascertain the texture of it. It had no hair apparent anywhere on its body, and seemed to wear no clothing, although slumped beneath a single blanket as it was, it was difficult to be certain. All the expected major appendages were present. The organ of generation was not visible, however, and facial features were -- well. They were off, somehow, in a way that was difficult to pinpoint. Sherlock's pen hesitated, hovering above the page of his notebook. How to describe the effect of eyes, nose, ears, mouth -- everything was there, and in vaguely the right places, but still everything was -- wrong? The mouth looked somehow ichthyic: gaping slightly with each lipless breath; nose devoid of structure; ears unnervingly mobile -- and those eyes! Black through and through, with no iris, no pupil. Impossible to tell where it was looking, what it was seeing.

"What do you see?"

Sherlock started. The creature had echoed his own thoughts. "What? What do you mean?"

"When you look at me. What do you see? I can see my arms and legs, and – body. I know I've become something... Something different. But I don't know what I look like. Not really. When – When you look at me like that that, Mr. Holmes, you don't seem disgusted or terrified, like the others do. So I ask you again: what do you see?"

Despite himself, Sherlock was touched by the question. There was a tremor in the creature's voice that sounded more than a little like fear.

Without a word, he spun on his heel and left the room. Within two minutes, he had returned with Molly's silver compact.

"Come to the glass," he said, watching closely. He opened the compact and held it up for the creature to see. "I've got a mirror. See for yourself."

There was a flurry of noise as the creature moved, then. Not the rustling of clothing or the crack of joints or even the groan of a grown man picking himself up off of the floor. It was not an animal sound; not an insect sound; yet it was organic -- alive. This was a series of muted clicks, as of tiny bits of metal bumping and rubbing against each other. And then--it was not quite that, either. Sherlock had never heard the like of it. He could feel that sound taking up residence under his skin, like fingernails scratching across a chalk board. He shivered, but the frisson he felt was not at all unpleasant. 

Slowly, the creature pulled itself up and shuffled closer to the glass. When it arrived at the transparent barrier that comprised its prison, it stopped and turned around, facing the rear of the chamber. The sounds it made grew muted, but did not cease. Tiny waves, almost liquid, ran over its skin in rhythm with its -- respirations? It hadn't sounded like this before. Looking more closely, Sherlock realized that what had seemed smooth from a distance was in reality a network of closely interlocking scales, so tiny as to be nearly indistinguishable to the naked human eye. Scales? What _was_ this thing?

"Don't you want to look? Here. The mirror is right here." Sherlock held it up, but the creature didn't turn. Nor, for a long moment, did it speak.

"I'm... No. I can't. I can't look, after all."

"What? _Why_?" Sherlock breathed, utterly stymied. How could anything -- anyone -- not want to look upon such a fascinating collection of oddities and impossibilities? He himself was rapt before it. Imagine -- imagine existing inside such a body!

But the creature was speaking. "I'm -- I'm not proud of this, but I'm. I'm terrified. Utterly. I can't -- I can't look at myself and not see myself. I think I'm going mad."

Sherlock scoffed.

"No--don't laugh. Truly. This is. This is insanity. Look. Look at me! This is not my hand. This is not my arm! I don't even know _what_ it is!" He held his appendage up to the glass. The skin, previously a flat, matte colour, now shimmered in a constant rhythm. As his body shifted, expanding and contracting with each breath, so did his skin, his -- scales? They grew and deflated, incrementally, with each inhalation and exhalation. The creature was shaking, slightly, and Sherlock wondered suddenly about species variation in physical fear responses. 

"Perhaps you have amnesia," he suggested suddenly. "How did you come here? Where did you come _from_? What do you remember? There must be something! How did you--how did you learn to speak English? You must see -- must see how extraordinary you are."

"It isn't me, though. Don't you understand? It's not extraordinary. _I'm_ not extraordinary at all. At least, I shouldn't be. This is a nightmare."

Sherlock shook his head impatiently. "Evidence suggests that it _is_ you, regardless of what you may believe. There are scientific inquiries we can pursue that will solve the mystery of--of _you_ , I suppose, but our work will be more efficient with your cooperation. Look in this mirror. Just look at yourself! This is you, man! You must believe the evidence of your own --" he winced. Were those even eyes? "You must believe the evidence!"

But the creature again shook its head in a strangely human gesture. "I don't know why you would believe me, but by God you're the only person to really listen to me since this whole nightmare began. I must try to make you understand," the strange creature whispered. "I think I must be mad. My name is John Watson, and a Martian has stolen my body."

*****

The strange pair had ended up sitting on the floor, face to face, with just the thin pane of glass between them. Sherlock heard relief in John's voice: relief that he finally had someone to talk to -- someone who actually cared to listen and even believe his strange story. Sherlock could not think of when he had had enjoyed himself more -- or felt more alive. Talking with the creature was extraordinary. After his initial, understandable hesitation, John Watson seemed to accept that Sherlock's motivations and methods were quite different from his brother's, and warmed to the man who apparently wished only to help him.

He allowed Sherlock to ask questions virtually unchecked, answering each with an understated but stolid intelligence that Sherlock found charming. He remembered a former life in vivid detail -- that of John Watson, late of the Fifth Northumberland Fusiliers, and recently discharged and seeking civilian work in London. Nothing about his story seemed at all unusual -- nothing, that is, until he woke up one day, changed.

"I keep trying," he was saying, Sherlock nodding encouragingly. "I've done nothing but wrack my brains since they brought me here, and I just don't remember. It's a blank -- a gap in my memory. Like I was unconscious. One minute I was walking up New Cavendish Street on my way to an interview at U.C.H. I remember I passed a cafe and thought I might have time for a quick coffee. Then -- nothing."

"Close your eyes, John," Sherlock said. "I want to try something, and I need you to concentrate."

"Wh-what? Why?"

"I want to try to maximise your memory via visual stimulation. Try to visualize what you saw. Can you picture it? The street? The cafe? As much detail as you can!"

"Yes, of course. I see it clearly."

"Excellent. Keep watching. Did you turn? Open the door? What happened next?"

John leaned forward suddenly, banging his head sharply against the glass partition. Sherlock jumped.

"Nothing. Nothing at all. I keep telling you! Just like I told them. You have to believe me!" His voice was rising in panic once more, and Sherlock raised a soothing hand.

"Of course I believe you, John. I was merely attempting a memory visualization technique. An experiment, if you will. Please calm yourself."

But at that instant, the door of the lab burst open and a half dozen uniformed security officers swarmed in, followed closely by an irate-looking Mycroft Holmes.

Sherlock growled in frustration--he'd lost track of time.

"This security breach is Gregory's doing, I imagine?" Mycroft asked. The security detail surrounded Sherlock where he was crouched on the floor, but they stood slightly back, awaiting further instruction.

"Who?" Sherlock asked.

Mycroft smiled icily. "Get out."

Sherlock rolled his eyes and turned his back on Mycroft. Making what he presumed to be eye contact with the creature, he whispered urgently, "John--listen to me. I will return. Mycroft can eject me now, but no lock in the country can keep me out. _Courage_ , yes?" 

The creature's scales were standing upright in what Sherlock now knew to be high emotion. He didn't answer, but placed his hand up against the glass. "Please," John said. "Please don't leave me here to die."

Sherlock pressed his own hand to the glass, then rose swiftly and left the lab without so much as a backwards glance.

"Sherlock?" Mycroft called after him. "There will be consequences for your actions here tonight."

There was no reply.

"No consequences for what you do, though, are there?" John asked, his voice louder and stronger than it had been all night.

Mycroft clenched his jaw and said nothing. He never spoke to the creature -- not anymore. Caring was a luxury he could no longer afford. 

"Alpha team, prep the creature for procedure 7.3," he said quietly.

John Watson shuddered, but said no more. He had found a glimmer of hope in the person of one Sherlock Holmes. He could handle pain.

He refused to beg.

*****

Sherlock Holmes plucked a printout from Dr. Molly Hooper's hand. "Ohhhh," he breathed as he quickly scanned the page. "This makes no sense at all." His pale eyes gleamed. "How absolutely brilliant," he murmured. The paper fell from his hand and he stared off into space, lost in thought.

Molly sighed and turned back to her station. Sherlock was quite correct, of course -- the results were nonsensical in the extreme, and suggested nothing more than the fact that her instrumentation had failed. Still, she knew better than to disturb a Holmes brother in thought.

She'd nearly finished recalibrating the first of her inorganic biosignature monitors – his overconfidence was anathema to her scientific rigour – when he suddenly he jumped to his feet, resuming their conversation as if there'd never been a pause.

"I guarantee you that the instrumentation is sound; you'll recall I adjusted it myself not two weeks ago when we received the Land's End meteorite shard. Ergo, the results are not impossible – merely improbable. Oh, Molly, it's Christmas!"

"Explain," she said flatly. She'd weathered his stormy enthusiasms before, and although there was no discounting his brilliance, his methods were often alarmingly inconsistent.

"Silicon, Molly! Think!"

"Silicon? How obscure. Yes, I think I've heard of it," she grumbled, rolling her eyes.

Sherlock ignored her evident irritation. "Silicon has many chemical properties similar to those of carbon," he mused. "It could -- theoretically, mind you -- create molecules that are sufficiently large to carry biological information." He'd proposed theories like this before to scientific colleagues, and had been met with nothing but ridicule. It was the reason he preferred to work alone.

But here Molly surprised him. "But where," she replied wonderingly, "would silicon-based life evolve? There's no place on earth that could support such a radical departure from our evolutionary path, and we've discovered no evidence of anything like it."

"Until now," Sherlock said, looking pointedly at the file on her desk.

"Oh! Well. Yes, perhaps. Until now."

Encouraged, Sherlock continued, "There are theories put forth by people who aren't even _me_ that parts of Mars might be up to 90% silica: reminiscent of the effect of hot spring water or steam coming into contact with volcanic rocks. Is this not an environment that is favorable to life? The silica may have been produced by the interaction of soil with acid vapors produced by volcanic activity in the presence of water. Based on Earth analogs, hydrothermal systems on Mars would be highly attractive for their potential for supporting the development and evolution of biological organisms."

But already Molly was shaking her head. "Silicon lacks the ability to form chemical bonds with diverse types of atoms, as is necessary for the chemical versatility required for metabolism. It's not a biological possibility, Sherlock." 

"Not in our biology. In _known_ biology."

Molly considered. She was silent for a long time.

"I suppose..." she said at last, haltingly and uncertain, "I suppose the existence of this extraordinary creature demands an extraordinary explanation."

Sherlock smiled, his eyes crinkling with pleasure. It was unusual for him to have a scientific ally, and he felt unexpectedly relieved to have won her over. 

"My thoughts exactly. Silicone-based chemicals would be more stable than equivalent hydrocarbons in a sulfuric-acid-rich environment, as is found in some extraterrestrial locations. Silicon compounds may possibly be biologically useful under temperatures or pressures different from the surface of a terrestrial planet, either in conjunction with or in a role less directly analogous to carbon. I've argued for some time -- in several top-tier journals, mind you -- that since polysilanols are soluble in liquid nitrogen, they could play a role in very low temperature alien biochemistry."

"I've read your articles," Molly said, cocking her head. "Your theoretical framing is sound, but your methodologies leave something to be desired."

Sherlock shrugged. "My results speak for themselves."

"Yes, well. As I recall, your results haven't exactly set the scientific world aflame."

He snorted. "That's only because the vast majority of people are idiots -- not least of all, my brother." He eyed Molly speculatively. "So what's he up to? What are these tests and procedures John spoke of? What are they doing that hurts him so?"

Molly winced. "He hasn't told me outright. But the preparations are pretty clear, don't you think? I have my suspicions. You must, as well."

Sherlock stared at her, aghast. "Surely not. Not _really_? He wouldn't! Vivisection of a living creature?! I've never known him to be purposelessly cruel."

"The problem is, it's not purposeless, is it? There's a wealth of data at our fingertips. I've tried to talk him out of it," she sighed. "So has Lestrade. He won't hear it."

"He'll hear me," Sherlock said grimly. "This must not happen. A sentient creature! My God!"

Molly looked at him in surprise, tilting her head. "It's the next logical step, Sherlock," she said thoughtfully. "Not kind, certainly, and not humane -- but a logical method for obtaining data."

Sherlock paused. Unfortunately, she was quite correct.

*****

Sherlock wasn't able to see the creature again for almost 24 hours. His brother had pulled Lestrade off of his official guard duties and replaced him with a contracted security service: all brawn and little brain. Sherlock snorted when he saw the man stationed at the door to Mycroft's lab. It would be nothing to distract him for the instant it would take Sherlock to slip inside.

It was the work of a few moments to enlist Molly's assistance.

"Wear the lipstick," he told her. "The red."

She sighed. "Why can't you do it yourself, Sherlock? I'm busy."

"Because I'm not a pretty lady. You are." 

Carefully, she resisted the urge to punch him. "For John, then." She followed him down the corridor and began the most outrageously sarcastic mimicry of flirtation Sherlock had ever seen. He sighed, inwardly. Not an actor, then, Molly.

Luckily, the guard was not a proponent of subtlety, himself.

"You owe me," Molly mouthed over her shoulder as she led the man away. Sherlock saluted her neatly. An instant later, he'd picked the simple lock and stepped inside the lab.

"John?" he called. "Hello? It's Sherlock Holmes."

The lights were blindingly bright in the lab, but it took Sherlock a moment to visually locate the creature, crouched in a defensive posture in the back corner of his room.

When he saw Sherlock, his entire body sagged back into the wall, all the tightness in his strange body seeming to disperse.

"Thank God," he said.

Sherlock noted that his voice was significantly lower and quieter than it had been the day before.

"John? Are you... well?" he asked uncertainly. “You sound different.” 

The creature's shoulders rose in a strangely human gesture. Familiar, but made strange on the alien body.

"It's hard to say. Hard to remember, almost. I can't..." his scales rustled in apparent agitation. "I don't know what I feel like when I'm well."

"Did they hurt you? My brother's cretins, I mean? What did they do?"

The creature shuddered. "They're trying to make incisions in my--my midsection. I don't know why. Well, I can imagine, I suppose." He unfolded, and Sherlock saw that a series of discoloured lines now ran up and down the creature's torso and abdomen.

He hissed through his teeth. "Is it painful?" It didn't occur to him until later that this was an uncharacteristic and unscientific question for him to ask first.

"Less so now. When they're cutting, it's... not pleasant."

"But -- 'trying.' You said they were 'trying' to make incisions. It didn't work?"

"It hasn't yet. I think they came close this time, though." He shuddered again. "The first time, they used simple scalpels. That was worse than useless--the scalpels just broke in their hands. I could barely even feel them. After that, the knives got bigger. They're experimenting with different materials. This time it was a diamond-bladed saw. I could--I could definitely feel it."

Sherlock's stomach clenched. He knew his brother would be desperate to analyze a sample of the creature's exterior scales for a variety of scientific and military reasons, and certainly he was trying to obtain such a sample in the most straightforward and logical way, but... he shook his head. It would be an unutterable travesty to destroy the creature, even in an effort to understand it. He had to make Mycroft understand.

"Come to the glass," he said.

The creature didn't move.

"Please," Sherlock amended. "I'd like to see what they've done to you. It will help me to formulate arguments to my brother on why these barbaric procedures must stop."

After a few moments, the creature stood and shuffled forwards. Its movements were slower than they had been previously, Sherlock noted, its posture more hunched.

"How bad is the pain?" Sherlock asked softly.

"It's alright. Nothing I can't handle. I'd like to get my hands on your brother, though. Teach him a lesson."

"We'd all enjoy that, yes," Sherlock replied absently. He'd dropped to his knees and was gazing at the creature's abdomen with rapt attention.

Row upon row of scales – now shining almost with iridescence, now sunk in flat opacity – shifted and transformed with every small movement the creature made. It was extraordinarily fine-looking.

"...almost did, the one time," John was saying.

"I'm sorry, what?" Sherlock blinked back to attention.

"I almost socked him one. Early on. I don't think he realized I could move much. He was talking to me like I was stupid, the arrogant tosser, and I was--I was half out of my mind. I lunged for him, fists out. Missed, though. I can't always judge things right, with my eyes like this. They haven't let me near him since."

Sherlock was delighted by this story. "I wish I had been there to witness that," he said sincerely.

John put his hand up to the glass. "I wish you'd been here since the beginning," he replied hoarsely.

Their eyes locked. Sherlock felt he was beginning to get used to the strange dark pools of the alien's eyes. They were fascinating -- and beautiful.

Sherlock cleared his throat. "You mentioned that your vision is different, now?" he asked, returning to more familiar territory.

John looked away.

"Just depth perception. It's the least of my worries."

"Even so." Sherlock took careful notes on his clipboard. "One never knows which piece of data could turn out to be vital."

"If you say so." John let out a tired-sounding chuckle.

"What about food?" Sherlock said suddenly. "Are you hungry? Have you eaten? _Do_ you eat?"

"I don't... I don't know. They give me water and food, but I don't think I need it. I don't want it. I tried, once or twice, but..." He broke off helplessly.

"You'd be dead by now if you needed water and hadn't had any, so we can certainly deduce with a high degree of certainty that the needs of your body are entirely alien in nature."

"What are they, though?"

"Yes, that is rather the question," Sherlock mused. "Do you feel any cravings? If I could bring you something right now -- anything -- what would it be?"

John growled. "I don't _know_! That's the problem. I feel so many different things, strange things, and they're all--off. I can't interpret any part of what this body is telling me, it's wretched, wretched! I don't think I can take much more, Sherlock." He slid down the wall and sat slumped against it. Sherlock took a seat on the floor at the glass, as well.

"Alright," he said, his voice sounding strangely gentle in his ears. "In that case, John, I'm going to tell you what _I_ know. Things I've deduced to be true. And then I will share some theories that I expect to be proved true in the fullness of time."

John looked up, his black eyes now flat and opaque.

Rapidly, Sherlock began to speak: "You're a medical doctor, so you have scientific training. Stop me if I lose you -- I don't expect to. Of the varieties of molecules identified in the interstellar medium, 84 are based on carbon while only eight are based on silicon. Of those eight compounds, four also include carbon within them. The cosmic abundance of carbon to silicon is roughly 10 to 1. This may suggest a greater variety of complex carbon compounds throughout the cosmos, providing less of a foundation on which to build silicon-based biologies, at least under the conditions prevalent on the surface of Earth. However, it is my contention that silicon compounds may possibly be biologically useful under temperatures or pressures found on different terrestrial planets, either in conjunction with or in a role less directly analogous to carbon. Polysilanols, for example, are soluble in liquid nitrogen, suggesting that they could play a role in very low temperature biochemistry. There are others, as well, of course. The universe is infinite, and our understanding infinitesimal."

"Silicone?"

"Silicone. Silicone-based life."

"But how could that be? How could--"

"I have absolutely no idea, but here we are. Here _you_ are. It's something of a miracle, to be quite honest. The fact is that you, John Watson -- your consciousness, and all your memories -- have been implanted, somehow, into an alien, silicone-based corporation the likes of which our world has never seen."

Sherlock rocked back on his heels, beaming. "Obviously, you are upset and disoriented, John, but think of it! You're also the first human being in all of history to have had this experience! You're a pioneer. And oh -- the body! It's beautiful, John. It's _fascinating_." 

A grating, angry sound filled the room.

The creature's scales flared up, mineral red, and he slammed his fist into the impervious glass. Sherlock jumped.

"Fascinating? _Fascinating_?!" His voice rose steadily until it was almost a bellow. "My life has been _stolen_ from me. Don't you understand? Everything. _Everything_! My -- my body is a nightmare. I'm tortured, daily. I'm trapped in a bloody glass prison, Sherlock, and I've turned into a monster! How _dare_ you call this fascinating?!"

"Are--are you panting?" Sherlock asked, eying the creature's heaving chest speculatively.

The creature growled, slammed his fist once more into the glass, and retreated to the back of his chamber where it hunched down, hiding as much of itself as it could from view. He refused to speak to Sherlock again for the rest of that night.

Sherlock, however, was nothing if not persistent. It became a nightly habit for him to break into Mycroft's lab and check on the creature. ("Good practice, too," he told Molly.)

John Watson rejected his first attempts at conversation, remaining slumped at the back of his chamber when Sherlock entered the room. Nor did he respond to Sherlock’s stuttering attempts to apologize for his insensitivity. But on the third night, he was standing at the glass when Sherlock slipped in – and it was he who spoke first.

“One thing you need to know about me, Sherlock, if we’re to be friends.”

Sherlock cocked his head, vastly relieved to be hearing that strange voice again.

“I’m a stubborn man. Well – a stubborn something, anyway. I’m sorry about the silent treatment. It wasn’t ... it wasn’t good of me. But you have to understand – it’s all I have left. To speak or not, that’s the only power I hold, and I” – he took a shuddering breath – “I was very angry at what you said. My life has been destroyed, and you made it sound exciting.”

Sherlock’s lip quirked. “‘Was?’ You _were_ angry?”

The creature’s scales rippled. “Am. Was. I don’t know. But I know you don’t mean to harm me. And you’re the only person who talks to me like a man. I—I missed it. I missed you.”

Sherlock nodded. “And I you. Truly, John, I am sorry. I meant no harm, no offense. I get carried away by scientific novelty, but I should not have forgotten that my study is your reality. It will not happen again.”

The creature nodded.

Sherlock looked down at his hands, avoiding John’s strange eyes. “I suppose there’s something you should know about me, as well.” He slid down to the ground beside the glass partition, unconsciously resuming the position he’d been in during their last conversation. “I’m not good at this, John.” He gestured vaguely between them. “I have been reliably and repeatedly informed that I am robotic in my emotions and freakish in the way I express them. I say the wrong things. I hurt people. Always. And most of the time I don’t even know _why_. I don’t have friends.”

The creature sat down beside him and put his hand to the glass. “You have one.”

“I—thank you.” Sherlock knew he shouldn’t trust this declaration from a creature who was so entirely in his power, but he did all the same. “I shall strive to be worthy.” 

*****

"You cannot keep him confined like this, Mycroft! It's not--it's not right."

" _Right_?" Mycroft raised a skeptical eyebrow as his brother paced manically before him. "And suddenly you are the arbiter of what is and is not ethical in the realm of scientific investigation, are you? All of your own work, for example, is strictly above board? Shall I have Brantherton conduct a facility review? He can do an ethics compliance sweep--starting with your lab, and ending with mine--and then we'll see your true attitude towards research ethics. Or perhaps it's time for another one of Lestrade's little searches, hmm?"

Sherlock flinched, then wheeled around on his heel so that his face was in the shadow.

"There's no need for that," he said more quietly.

"I'm glad to hear it." Mycroft's voice was brisk. "Now if you wouldn't mind, I'm quite occupied this afternoon--" He gestured to the door.

"No, Mycroft, wait. You really cannot continue with this. John is a man--whatever he might look like. He's not an animal, he's not an experiment, and you cannot keep him locked up."

Mycroft sighed and glanced at his watch. The project was already running grievously behind schedule. How often, he wondered, would he be called upon to deliver these platitudes? He had known that Lestrade would take some finessing, but had not thought his brother would demand such reassurance. And the Prime Minister would not accept further delays.

"Sherlock, you are a man of science, as am I. What would you have me do? Let him out to roam the streets of London? Imagine the panic! This creature is entirely outside of the realm of what is known to us. We simply have no idea what it is or where it came from. Think of the scientific gains to be made! Think of what we can learn from careful study."

Sherlock snorted. "You wouldn't care a jot for what you can learn from it if you weren't convinced it would give us a tactical advantage over the Russians in weapons development -- and consolidate your power over the Prime Minster."

"That is not the case, I assure you. You're thinking in absolutes, which is the surest sign of an immature mind. Govern yourself at once!"

The pair glared at each other across Mycroft's heavy desk, neither willing to be the first to break eye contact.

Finally, Sherlock blinked. To Mycroft's surprise, he looked down at his hands, which were shaking. When he spoke, his voice was low. "Your experiments – they cause him pain. Agony. Have you observed? Have you--have you spoken to him, afterward? His name is John, you know. John Watson. A British citizen. And you're torturing him. It must not go on. There are other ways to learn."

Swallowing his astonishment, Mycroft allowed himself a small sigh and his face softened, slightly. He must not permit an attachment to form. "Caring is not an advantage, Sherlock."

Sherlock stiffened and pulled back, his face falling into a neutral mask. "I'm sure I don't know what you mean."

Mycroft smiled grimly. "Good. Then there should be no issue. Make sure you keep it that way."

Sherlock spun on his heel and stormed out the door.

Mycroft sighed and pressed a buzzer on his phone.

The speaker came to life immediately. "Sir?"

"Matters are becoming urgent. I’m moving up the vivisection. Proceed with the preparations; you have 48 hours."

*****

Despite Sherlock’s protestations of social isolation and unmitigated rationality of thought, there were several individuals who harboured a great deal of fondness for the man – and he for them, reluctant though he was to admit it. Lestrade was one; Dr. Hooper another. And both were becoming somewhat uneasy about his increasing obsession with the strange creature known as John Watson. They’d seen what damage Sherlock could do to himself in the throes of intellectual frustration, and they feared the destructive power of his mind as much as they admired its inverse.

“Sherlock?” Molly asked timidly, picking up the cold, untouched tea she’d left in front of him several hours ago.

He didn’t respond.

“Sherlock?” She spoke again, louder this time, and determined not to leave him alone with his thoughts. “I want to help the creature – Dr. Watson, I mean – too, but I’ve no idea where to start. Let’s work together –something! Where can we start? We can't just sit here and twiddle our thumbs!"

Sherlock suddenly came back to himself with a shudder. He sighed a sigh of grievous disappointment. "When have you ever known me to 'twiddle my thumbs,' Molly Hooper?"

"Well, and why not?" Phil Anderson piped up, wandering past with a large coffee in his hand. "That course seems eminently prudent to me. In fact, at the present time, thumb-twiddling is distinctly indicated. Mr. Holmes told us not to interfere. I say we listen to the very powerful man who pays our salaries."

Sherlock rolled his eyes. "What we need is a way to track the energy signature thrown off by the alien presence inside Watson's body."

"Assuming the creature is telling the truth, and isn't just insane or a pathological liar," Anderson smirked.

"Yes, assuming that. Thank you, Anderson. As usual, you've lowered the I.Q. of the entire room." Sherlock turned his back on the hapless technician and continued. "I have not been idle, these past hours. I’ve been deep in my mind palace, evaluating seven possible lines of inquiry that may be fruitful. As time is unfortunately pressing, we must choose our course of action well. Now, externally, the alien in Watson’s body will look like any other human on Earth--and he could be anywhere! We'd never stand a chance of locating him--even just within the city of London. And he could be anywhere on the planet by now! But that energy signature should be unique, and it should be incredibly concentrated and powerful.

"In terms of tracking him down, I believe the task may not be as hopeless as it first seems. There are several limiting factors that we can assume to be in play, and additional scientific calculations should make it possible to estimate a likely radius, at least."

Molly snapped her fingers. "I was reading up on the latest from MI-6--they've got a new radar scanner built of dagal, which is good stuff, but it isn't as good as your purple metal, inoson, Sherlock. When you developed that, I was sure you'd sell it for millions! Inoson should theoretically detect any energy patterns out of sync with its surroundings--at least, any material possessing molecular structure."

"Molly! You genius!" Sherlock grabbed the woman and kissed her forehead.

"You really think it will work?" she asked, flushed and pleased.

"Work? No, no. Of course it won't work. You've neglected to consider the Castalor principle. However--" He raced to the large cabinet on the far side of the room and yanked it open, pulling out a dusty box.

"It occurs to me that inoson might have other applications as a visualizer if we run it through a series of astron energy protocols. It may be possible to install a very complete fifth-order projector right here in the lab--or rather, on the roof above the lab--that would allow us to scan for energy discrepancies. It would require a very particular lens array..." He broke off, staring into space.

Several minutes later, he continued as if there had been no pause. "Factoring in Watson’s height and weight, that size of scanner should be able to find him anywhere up to about a thousand miles. And quite frankly, I don't believe he's left London. Where is his logical destination? It can't be far--not if he's as weakened in Jo--in Watson's body as Watson is in his. He doesn't have compatriots here, at least none that we know of – and Mycroft would know. No, logic dictates that he must be in London."

"Hmmmm," Molly nodded, distracted. "But Sherlock, won't the magnetic field arising from the inoson reactions heat the apparatus to an unusable degree?"

Sherlock tutted. "I think you know me better than that. I've got three pumps I can put on that job, in series. First, a Rodebush-Michalek super-pump; then, backing that, an ordinary mercury-vapor pump; and last, backing both the others, a Cenco-Hyvac motor-driven oil pump. In less than... let’s estimate fifty hours from now, the inoson scanner will be charged enough for efficacy. Just to make sure of eliminating the last infinitesimal traces of impurities, though, I'm going to flash a gatter charge of tantalum through it. After that, the atmosphere in the case will project an image of the energy patterns of the surrounding area onto a calibrated visi-plate. Take my word for it. It’s going to work."

Anderson groaned and returned to his bench, peppering his retreat with the rudest of gestures, but Sherlock and Molly were too engrossed in their work to even notice.

*****

"I need to get some air,” the creature gasped. “I haven't been outdoors in--I've no idea how long, actually. I can't tell if it's night or day, or how many days have passed. I can't breathe in here."

Sherlock was seated in his usual place, on the floor alongside the glass partition in Mycroft’s lab, watching John’s strange scales bristle and quiver in intoxicatingly beautiful patterns that Sherlock thought must denote acute mental distress. He did not mention his delight at the beauty to John, having learned from his previous experience that such would not be well received. His rapt observation was entirely covert.

"I can't see a way to get you out of here," Sherlock admitted, tugging his hair in frustration. "I'm sorry. I don't think it's possible. Even if I could open your cell, we'd still have a dozen hallways on two very populated floors to make it through, and you're not exactly inconspicuous in your current form."

The creature made the sad clicking sound again and seemed to shrink further into itself.

Sherlock straightened up suddenly. "Listen," he said. "I can't get you out, but perhaps I can make things slightly more pleasant for you." He sprinted from the room, ignoring John's protests.

"Christ," John muttered. "It's not better when you're not here." He slumped heavily on the floor, a picture of defeat.

A moment later, however, Sherlock bounded back into the room, a black case tucked under his arm.

"I play," he said rapidly, removing a violin from the case and placing it carefully under his chin. As he tuned the instrument, he babbled. "I know it's not the same as experiencing the outside world, but perhaps it will be better than nothing. I haven't played for an audience in -- in many years. You'll excuse me, I know, if I overstep or play too shabbily."

"You play the violin?" John asked rhetorically. "Of course you do. I don't know why I'm surprised."

Sherlock coloured. "My parents insisted I learn when I was a boy. I'm sorry, I know it’s silly. I don't know what I was thinking. Never mind." Quickly, he tucked the instrument back into its case and slid it under the lab bench, out of sight.

"No! No, Sherlock. That's not -- that's not what I meant. At all. I just meant that you're -- you're brilliant. Your talents are extraordinary. I should have known you'd be a musician, as well."

"Yes, well. I shouldn't have offered to inflict my taste on you, at any rate. I've been told it's esoteric to the point of abstruseness."

A mechanical grating noise came from the creature. Sherlock didn't know how to interpret it.

"Play for me," the creature said. "I'd love to hear you, to hear something--human. Please, Sherlock?"

"Any requests?" he asked, tucking the instrument into his chin and flexing his hand. It had been too long since he'd last played.

John snorted. "I wouldn't know enough to name a single song. Haven't had anything to do with proper music since my school days. Played clarinet in the junior orchestra for two years -- that's the extent of my musical knowledge and training."

Sherlock smiled, helplessly charmed. "Clarinet?" he murmured. "A criminally under-appreciated instrument."

"Well." The creature’s scales rippled. "You wouldn't say that if you'd heard me then."

Sherlock smiled and began to play. Thinking to provide a comforting soundscape for the agitated creature, he began with Chopin. Insipid, he'd always thought, but the effect the music had on the creature was immediate and profound. The strange movements of his scales stilled, and their colour began to level out into an opaque blue, shot through with a thread of deep purple so rich it almost appeared to glow. He played through several nocturnes, Massenet's "Meditation" from Thaïs, and some unfashionably early Debussy. Quite unexpectedly, Sherlock found himself enjoying this performance in a way he never had before: it felt as if the notes left his hands, his instrument, and landed on John almost like a touch, gentle and soothing. Watching John’s response, he adapted his own playing, tempo and tone. Gradually, there coalesced a tenuous feedback loop between them: music, colour, sound, and even – sensation.

Sherlock shivered. Pleasure vibrated between his hands, his strings, his bow, and John’s scales. Without thinking, he shifted into Holst’s Planets: Venus, he played, bringer of peace and of love. Eerie. Slow. Beautiful. 

As he played, the now-smooth surface of John’s body shimmered, shook, then slowly changed, revealing the seams of its interlocking scales. Sherlock had seen a version of this physiological response before, but as the music continued, it intensified and transformed. In slow waves that crested in time with the music, the scales pulled back, retracting, opening, and before Sherlock’s astonished eyes, began to emit something – something indescribable. Emerging from the creature’s newly textured skin were wispy tendrils of sound-made-visible: almost--but not quite – corporeal.

Staggered, Sherlock realized that John was singing with light: music without sound, image without substance.

“John?” he whispered. “What—”

“Please don’t stop playing,” John sighed. “Don’t stop. Feels good.”

Sherlock, riveted, carried on. He felt that he wanted -- something. He wanted something desperately, felt filled to the brim with objectless desire. He didn't know what to do about it. He wanted -- first of all, he wanted to hear more. Those sounds! A field of crickets, but -- more velvet. The beating wings of a flock of birds, but -- more focused. Insistent. A rumble like distant thunder, but gentle, promising needed rain.

John’s apparent pleasure heightened Sherlock’s own. His breath caught in his throat, each note he played pulling new reactions out of John, and cascading back onto him, sounds running like fingers over his body.

He shivered as he came to the end of the song. In the charged silence, the creature closed its eyes and sighed deeply.

As Sherlock watched, its scales crept slowly back into place, skin impenetrable once more.

He swallowed, awed. “John,” he said. His voice was rough. “That was—”

“Bliss,” John interjected. “It was bliss.”

Later that night, Sherlock opened his notebook to record careful notes on every observation he had made. For him, the drive to understand the unknown had always seemed as vital as his baser physical drives-- _more_ vital, even. The desire was the same: to consume, and by consuming, to know. Physically, intellectually, scientifically, sexually – there was little enough difference, when it came right down to it, but he’d never experienced the heady merger of all forms of desire at once before. Recognizing the impulse for the insanity it was – knowing what it might look like – knowing, even, what the consequences could be – Sherlock acknowledged to himself that he wanted John Watson in every way that a person could want. He stared helplessly at his notebook, at a loss for words. He’d learned how to penetrate the creature’s skin, and science hadn’t had a thing to do with it.

*****

When Sherlock next entered the creature's lab, it was 48 hours later and he hadn't slept a wink nor had he consumed more than a cupful of milky tea and a couple of biscuits (on Molly's insistence). His entire existence, mind and body, were focused, laser-like, on the vital work he had to perform if he had a chance of saving John Watson. For all his confident words to Molly, he knew that the likelihood of success was vanishingly small. He'd never admit it in front of Anderson, but he knew his theories were untested and his equipment a Frankensteinian amalgamation of parts scavenged from various contacts and Mycroft's rubbish bins.

Every time his mind slowed down enough to reflect upon their situation, fear lanced through his veins. They would be very, very lucky if his plan worked out as promised.

He clenched his fist. They _would_ be lucky. They had to be. 

The creature's condition was deteriorating rapidly, and he didn't think the steepening rate of decline could be attributed entirely to Mycroft's barbaric procedures. Every time he saw him, the creature's scales seemed duller in appearance, his movements slower, and his voice softer.

 _Lifeless_ , Sherlock thought to himself, with an unfamiliar pang of emotion that he identified as concern, but which more truly approached alarm.

It was so unlike the adamant, enraged, frantic personality he had met on the first day that he had to swallow a sound of distress.

"John!" he said, his voice cracking.

John was on the ground. He'd apparently been crawling towards the glass partition when he'd lost all strength and collapsed.

John opened his eyes, but did not -- could not -- raise his head.

"Sherlock?"

"Christ! John. What's happened?"

"Nothing," came a dreamy reply. "Nothing at all. Just. Can't seem to move much..."

The voice trailed off, seemingly unconcerned.

"What are you -- what are you feeling? John! Please concentrate. I need to understand what's happening. What are you feeling?"

"I'm fine, Sherlock," the creature said. His voice was milder than Sherlock had ever heard it. "Doesn't hurt. Just tired. It isn't so bad, lying down."

Sherlock ground his teeth in frustration. “Are you thirsty? Hungry? What do you need?”

“Isn’t so bad...” John repeated.

And then he spoke no more.

*****

Sherlock sprinted into his lab, a look of absolute determination on his face.

“It’s going to work,” he said. It wasn’t clear who he was addressing, but no one within earshot – Molly, Anderson, Donovan, Lestrade – had any doubt as to how serious he was. It was going to work or Sherlock would fall into oblivion: one of the two outcomes was assured.

“Molly: with me,” he ordered, handing her a clipboard list of instructions. The two gathered around the instrument-board and Sherlock explained the changes he had made--and to Molly it was soon evident that they were examining an instrumental control panel more advanced than anything she'd seen -- or even heard of -- before. It was a system which only the virtuoso mind of a Holmes could have devised. The new object-compasses were housed in arenak cases after setting, and the housings were then exhausted to the highest attainable vacuum. Oscillation was set up by means of one carefully standardized electrical impulse. The bearings, fabricated with arenak and telapian metals, were as strong as the axles of a truck yet almost perfectly frictionless.

Molly nodded silently.

"I'm pleased with it," admitted Sherlock. "Without friction, the plates will rotate freely more than a thousand times per minute on the primary impulse, as against a few minutes in the old type; and under load they are many thousands of times as sensitive."

"Cracking!" declared Gregory enthusiastically. "That’s as far ahead of Mycroft's model as the aliens are ahead of Wright's first glider."

The other instruments were no less noteworthy. Sherlock had adopted the Perkins telephone system, but had improved it until it was scarcely recognizable and had made it capable of almost unlimited range. He had devised full automatic directional controls, and meters and recorders for detection, distance, and angle.

"This takes my eye, I must say," Molly exclaimed as she seated herself and swung a large, concave disk in front of her, experimenting with levers and dials. "When you look through this plate, it's better than looking out of a periscope--it subtends more than the angle of vision, so that you can't see anything but out-of-doors--I thought for a second I was going to fall out. What do you call it?"

"John calls it a 'visiplate'," Sherlock replied.

"That's a good word. I've never seen such a perfect mechanism. The set of lenses and prisms is absolutely exquisite."

"Thank you, Molly. It was -- in all honesty, I wouldn't have thought of that precise combination without John's ideas on diametric refraction.

Molly looked at him in surprise. She'd never known him to admit an intellectual failing before.

"Well!" Sherlock said brightly, swiftly changing the subject. "Shall we?"

All sound in the lab ceased as the laboratory team began to prepare in earnest.

Molly was entirely focused on her display panel, from which she was to monitor both instrument readings and Sherlock's verbal instructions for adjustments during the length of the search--however long it might take. Sherlock, meanwhile, was making final checks on his controls, ensuring perfect calibration.

"The next window of opportunity in the earth's electromagnetic fluxographic cycle will commence in approximately 12 hours," Sherlock announced suddenly.

He leapt into the viewing station and pulled the visiplate towards himself. “No trace of chromatic, spherical, or astigmatic aberration," he reported in surprise. "The refracting system is invisible--it seems as though nothing intervenes between the eye and the object."

"You perfected all these things since in just a few days, Sherlock! You _are_ in a class by yourself,” Molly sighed. “I couldn’t even copy them in less than a month, and I never could have invented them."

"I did not do it alone, by any means. John, even in his current state, was intensely helpful. He is not bright himself, I suppose, but he certainly is a conductor of light.” _Quite literally_ , he added to himself, remembering the wonder of John’s alien body opening to the music of his violin. He smiled to himself. John Watson: his friend.

*****

The next twelve hours dragged with terrible slowness. Sleep was impossible and eating was difficult, even for Molly and Lestrade, though all knew that they would have need of the full measure of their strength. Sherlock Holmes took tea with a little sugar, but otherwise only paced furiously and without cease. He would not visit John, his mind shying away from the image of what he might find. _No_ , he told himself, _better to let him rest_. To keep himself from going mad, he set up various combinations of switching devices connected to electrical timers, and spent hours trying, with all his marvelous quickness of muscular control, to cut shorter and ever shorter the time between the opening and the closing of the switch. At last he had worked it down to an open period of one one-hundredth of a second. Only then was he satisfied.

"A hundredth is enough to give us a look around, due to persistence of vision; and it is short enough so that the aliens won't see it unless they have a recording observer set on us. Even if they still have rays on us, they can't possibly neutralize our screens in that short an exposure.”

And then there was nothing at all left to do. The team sat silently in the lab, watching the clock creep forwards with agonizing slowness.

Finally, finally, the moment approached.

Sherlock took a deep breath. “All right? Is everyone ready?” The countdown clock showed that there remained scant minutes until their window opened.

Everyone nodded solemnly. They knew this was likely to be their only chance.

“We'll take five visiplates and cover the sphere,” Sherlock directed. “Two for me, one each for Molly, George, and Anderson. If any of you get a reading, it will be him. Be sure to mark the exact spot and outline on the glass."

Molly began to count backwards from ten. “Ten, nine, eight, seven, six, five, four, three, two, one—”

Sherlock flipped his switch. The stars flashed in the black void for an instant, then were again shut out.

"Here he is, Sherlock!" Molly cried. "Right here--he covered almost half the visiplate! It was incredibly clear."

She outlined for him, as nearly as she could, the exact position of the object she had seen, and he calculated rapidly.

"Excellent!" he exulted, copying coordinates down into his notebook. "He's within half a mile of us, three-quarters on--perfect! I feared he'd be so far away that I'd have to take additional readings to locate him. He hasn't a single ray on us, either, from what I can tell. The game is afoot!"

And Sherlock Holmes ran from the room.

*****

The body of John Watson reclined in a massive armchair, the fingers of his right hand lightly touching those of his left, his head cocked as if listening attentively to something within himself. It was a strange, unnatural posture, Sherlock thought -- more unnatural even than the sound of John's voice emanating from the body of an alien creature. Sherlock Holmes strode up and down the room, trying – as he had been for the last several hours – to convince the recalcitrant creature to accede to his request. His unruly curls standing on end, he spoke savagely around the burning end of yet another reeking cigarette.

"I can't force you. There's no use in my pretending otherwise. Your technology is far superior to anything I've got access to, and your biology is -- well. You have certain abilities which I do not. I cannot force you," he said again. "But" -- his voice took on a desperate edge -- "you must! You must return to your own body, and get Watson back into his. There's no other option! Not if you want to come out of this adventure alive, at any rate."

The creature's movements, expressed by John Watson's body, looked obscene. Where a human might have shook his head or shrugged his shoulders, the creature cocked its head at a strange angle and peered up at him, a strange combination of human and alien.

"I know I'm dying," it said after a time. "And he's dying. We can't sustain the energy expenditures required to keep us in these bodies. But I haven't figured out how quickly our cell energy is extinguishing. It must be pretty slow."

"Pretty slow?" Sherlock hissed. "You don't _know_? This is a matter of life and death! What kind of moronic, irresponsible, hare-brained foolery is this?"

The creature inside of John growled and clutched at his head. "If my head wasn't made of this hideous mush I'd have had a way out of this thing figured out before now, but I can't. I'm so slow in this body that I can't figure out how to use it intelligently—can barely use it at all, for that matter. It must be opaque to our energy rays. I can't use it at all! It drives me frantic!”

"You’re getting idiotic, " Sherlock rejoined with deceptive calm. "You caused this: you brought harm onto yourself and onto an innocent Earth life. You _caused_ it; you can reverse it.”

“I won’t. I won’t go back.”

“Won’t?” Sherlock raised a brow. “ _Won’t_ is different than _can’t_ : it implies only a lack of will.”

“Won’t, can’t – what does it matter? I’ll be dead before long.”

“I refuse to accept that,” Sherlock said grimly. “If you die, John dies. I will not allow that to happen.”

“There’s nothing to be done about it.”

Sherlock blinked rapidly, then sunk to the floor, the picture of defeat. 

Beside him, silently, John Watson’s human body continued its march towards death.

*****

Meanwhile, in a cell far beneath Diogenes Laboratories, the alien body containing John Watson’s consciousness lay unmoving and unresponsive on a sterile gurney.

*****

Mycroft Holmes drove quickly to the rear parking lot of the laboratory complex. Pulling into his reserved stall by the private rear door, he sat in stillness for a moment. He did not relish the task he had before him, but it was necessary, he reminded himself. And he had always been the man to accept the necessary but distasteful tasks – it was the secret of his expansive power and influence with his country’s government. This was no different from any of the many experiments he had carried out in the past -- for the greater good.

The creature’s flesh had so far proved impervious to all his attempts to pierce it, to learn from it, but he was certain his latest tool—a blade made of experimental wurtzite boron nitride—would be more than adequate to the task.

He rubbed his eyes. He couldn’t remember the last time he’d slept. He’d need to soon, he knew, but it could wait a little longer. God knew, the creature wouldn’t live much longer regardless of his interventions. It was a kindness, perhaps.

Gathering himself, he opened the door of his car and stood, removing his case and ever-present umbrella from the seat beside him and turning to lock the door.

In that instant, the world around him was suddenly flooded with an agonizingly bright light. He staggered, almost fell to his knees, unable to see a source.

“Human,” a booming voice said. It was in his ears, but also inside his head. Still, he could feel no directional indications that would allow him to pinpoint its origin.

“What is this?” he asked sharply. He had suppressed his panic within a millisecond of the commencement of the attack – for an attack, it surely was.

“Human,” the voice said again. “We require the return of the creature you have contained in your facility.”

“Ah,” Mycroft said, mind racing. He needed to buy some time. “What makes you think I have a creature of any sort?”

“We will not waste our time, human. If you do not return this creature to us within one of your Earth hours, we shall be forced to take him.”

Mycroft shuddered, despite himself.

Suddenly, the light was gone, and Mycroft was standing alone in a dark parking lot.

*****

Sixty minutes passed in a heartbeat. Calling for his brother, Mycroft discovered his absence and, at Molly’s insistence, sent a full retrieval team to the coordinates she provided with instructions to return Sherlock and his ‘guest’ to the facility immediately. As much as Mycroft disliked taking orders (and even, truth be told, suggestions), he was a fundamentally pragmatic man. He knew had had no hope of resisting the might of alien technology. He ordered the captive creature be brought up to the surface level, in preparation for making the exchange. It appeared to have lost consciousness several hours ago. Any security risk it represented was more than balanced out by the threat of extra-terrestrial invasion.

At the 47-minute mark, Sherlock returned to the facility with an apparently human body in tow: weak and feeble, barely conscious. He sprinted to Mycroft’s office, but was summarily ejected by a firm Gregory Lestrade, who filled Sherlock in on the situation.

At the 58-minute mark, Mycroft rose from his desk. He straightened his tie with hands that barely shook at all, then cleared his throat, and picked up his umbrella--perhaps the only nervous habit he still permitted himself.

At the 59 minute mark, he strode purposefully to the door of his facility, and looked up into the dark night sky, Gregory Lestrade on one side, Sherlock Holmes on the other.

At the stroke of the hour, the familiar, piercing bright light returned, flooding the parking lot and all but blinding the men in attendance.

And then Mr. Mycroft Holmes stepped out bravely into the weird, eerie circle of light that shone down blindingly from the otherwise dark night sky.

"It is my great honour to welcome you to our planet on behalf of the government of the United Kingdom of Great Britain, and indeed of the citizens of the world. We are delighted" – there was barely a hitch in his voice – "that you have found it possible to travel such a vast distance to introduce yourselves to us. On this truly historic occasion, we are concerned only with establishing friendly relations between us, and building cordial communication for future encounters. We trust that tonight's exchange will be beneficial to both of our constituencies."

All during this official and – Sherlock thought – officious speech, the light shining down on Mycroft Holmes intensified. As he finished speaking, a low hum filled the air.

Gradually, the men became aware that the hum was, in fact, some kind of amplified voice--and that it was speaking to them.

"... will not return." Meaning coalesced from the humming sound around them, almost without the intervention of words, or of language.

"Dear Lord, what technology is this?" Sherlock murmured, but Mycroft shot him a warning look and he subsided.

The strange voice continued: "We apologize for the actions of the Traveller Tryoquatt Erklits, who is a criminal and should never have come to your planet. He does not represent us. He has harmed you, and he will be tried and punished for his actions."

"I thank you," Mycroft said into the painfully bright light, "and accept your word, on behalf of Earth. If you could inform us as to the technology and procedures used to return John Watson's consciousness to his own body, we shall consider this matter most peaceably and satisfactorily resolved."

"Brother, no!" Sherlock muttered under his breath. "You know that we cannot do this. We must above all ensure John's safety! And then, there must be reparations. We must seek justice for the wrongs done against Dr. Watson."

Mycroft turned his back and continued, "We wish to proceed in the spirit of friendship. My people are most interested in learning from you, for you are far advanced in many technologies that we have only just begun to develop. We can offer you much knowledge in return! We have--"

" _Enough_ ," the strange voice boomed. "We have no wish to prolong our intercourse with your species, and we certainly will not provide your vastly inferior species with such dangerous technological abilities. Bring forth the bodies and let the procedure commence!"

"Oh, I'm sure that if you reconsider, you'll find that humans are--"

The hum twisted in the air, an almost palpable thing, and the sound rose and rose to a near-unbearable pitch. All the humans within range slapped their hands over their ears, writhing in pain. Mycroft, who stood in the centre of the brilliant ring of light and who had thus experienced the most direct blast of the Martian's – annoyance? – fell to his knees, gasping.

The sound lowered to more bearable, comprehensible levels.

"Bring forth the bodies," it repeated.

Mycroft removed his hands from his ears and shakily stood. He nodded his head. Behind him, the door to the building swung open and Lestrade stepped out guiding the manacled human body of John Watson. He half-dragged, half-carried the limp body into the circle of light. Meanwhile, Molly Hooper wheeled out a great mass covered in a thin blanket and lying on a gurney--the alien Traveller Tryoquatt Erklits. She halted beside John Watson's body.

"Here they are," Mycroft said. His usual hauteur was visibly absent. "How shall we facilitate this process? What can we... how can we help?"

The aliens ignored him completely.

Sherlock's gaze moved rapidly between the two bodies, timing respirations. "Please hurry," he said aloud. "The physiological stresses of cross-species habitation are almost too much -- for both life forms. If they are to live, they must be switched back now."

He realized belatedly that he was pleading.

"Be calm," the alien voice hummed. "We will not allow further harm to befall your mate." 

"My... what?" Sherlock blinked rapidly. "No, you don't understand. He's not my mate."

There was a pause. "There are no errors in our inter-personal data spectrometer readings; we are quite certain. But perhaps we misunderstand the term as your species uses it. We apologize. No further harm will come to your... John Watson."

"Thank you," Sherlock murmured. Mycroft was looking at him strangely.

There was a sudden crack -- like thunder, but less organic, more machine-like -- and the eerie red alien light flashed blindingly. Sherlock, along with all the other humans, pressed his hands to his eyes in agony, the sensory input too vast, too _alien_ , for their bodies to parse. Pain, their brains seemed to decide after a split second of hesitation: the sensation could only be interpreted as pain. 

For several seconds, it was all they could do to simply endure the barrage of sound and light. And then, just as suddenly as it began, it was over.

When they came back to themselves, shaking and strangely exhausted, the alien presence was gone: the night sky clear of everything except a slim crescent moon and a million, billion stars. Their ears felt muffled in relative silence of the London streets.

"Is anyone injured?" Mycroft asked. His normally commanding voice sounded puny -- almost comically so -- in the wake of the powerful alien barrage.

Everyone in the small group shook their heads in the negative. Mycroft exhaled in relief.

"Good," he said, almost breathless. "That's good."

Sherlock, however, felt a stab of sudden panic. "John?" he cried abruptly, rising swiftly and scanning the cluster of prone bodies now stirring on the ground where they fell. "John?"

A hand snaked out and cool fingers circled his ankle.

"I'm here. I'm alright, Sherlock." 

Sherlock fell back to his knees. "John," he breathed. "Is it... is it really you?"

John's eyes were still sealed shut, but he let out a shaky laugh. "I don't know. Is it?"

Sherlock knelt beside him. The tension in John’s body was obvious. His face was screwed up; his hands clenched where they lay on the ground beside him, and his shoulders were drawn up around his ears.

Sherlock had thought that the alien body was the most beautiful thing he’d ever seen, but he knew now that he'd been wrong. He ran his hand over John's worried brow, over his softly stubbled cheek. "Open your eyes, John," he said.

John shuddered. "I'm so afraid," he whispered. "Promise me, Sherlock. Promise me that I'm back--that it's real."

"I swear it."

John shook his head, eyes still locked shut. "I want to believe you, Sherlock, I do, but..."

Sherlock reached out and took John's left hand in his own. He drew the hand up to his own face, and placed John's hand against his cheek.

"Concentrate on my face, John. Focus on how it feels against your hand."

John nodded desperately, frantically, eyes still closed. His hands were calloused, strong, but trembling against Sherlock's cheek.

"You're so soft, Sherlock. Your skin is -- it's beautiful. I feel a little bit of stubble against my fingers, but it's soft. So, so soft... It's different from--from how everything felt before."

Sherlock swallowed hard. "Good. Remember that. Remember the sensation. And now--"

He guided John's hand from his cheek, to John's own face. 

"What about that? How does that feel?"

"Oh, God." John was crying. Sherlock watched helplessly as tears ran down his beautiful face, guided into rivulets by paths worn of experience. He had a lifetime of things to learn about this man, he thought, and the thought filled him with joy.

The tremor in John's hands grew stronger. "I think it feels the same, Sherlock. Please. Tell me? Does it? Is it the same?"

Sherlock smiled. "Trust the evidence of your senses. You're back. You're here. You're safe with me. Open your eyes."

John did, and the first thing his eyes met were Sherlock's own, looking warmly down into his. Quickly, Sherlock reached into his pocket and drew out a compact mirror. He held it up to John.

"There you are. See? Right as rain."

John grasped the mirror and drew it to his face. "I am. My God! I truly am! Sherlock, I didn't believe it was possible!" He dropped the mirror and pulled Sherlock into a fervent embrace. Sherlock almost overbalanced, but caught himself with his knee and hugged back for all he was worth.

"You've got to learn to trust me, John," he said silkily. "Obviously it was possible. It all came down to science."

John groaned softly, and tilted his forehead against Sherlock's. Their breath mingled, and their eyes locked.

"Thank you," John breathed. "You did this for me. I was a dead man, a dead -- something -- until you came along."

"Of course, John," Sherlock said helplessly. "Of course I'd help. I'll--I'll always be here for you."

John swallowed. Sherlock observed that his eyes were on his mouth, and then he stopped observing anything at all, because John Watson was kissing him. And Sherlock was kissing back.

A sound interjected itself unwelcomely between the two men. Mycroft, Sherlock registered. Mycroft clearing his throat.

"If you've _quite_ finished, gentlemen?" he asked, and there was a surprising (and utterly galling) tone of amusement in his voice. "We need to get Mr. Watson to medical immediately. We have no idea what the physiological ramifications of his recent misadventure might be, nor the after-effects of enduring such an ordeal."

Still kissing Sherlock, John held up a two-fingered salute. The ordeal he'd endured had indeed been difficult, but he had no intention of letting Sherlock go now. Not for Mycroft--not for anything.

*****

Epilogue

Undersecretary Tretaske of the Secondary Council of the Galactic Consortium for Justice proclaims the Proven and Verified Guilt of Traveller Tryoquatt Erklits, of espionage, treason, murder, and subsequent crimes against a lesser species. Undersecretary Tretaske further orders him detained on penal planet 719 for a period of not less than 3.74 I-galactic temporal periods. During his period of detention, he shall be deprived of any and all contact with his nestlings, inclusive of psychic joinings, and shall subsist on planetary rations of 7 nutritional capsules per cycle. Rehabilitative programming to be provided as deemed appropriate. As decreed, so shall it be.

**Author's Note:**

> The very very silly pseudoscience in this story is inspired partly by the very very silly Skylark Three by Edward E. Smith, available on Gutenberg: http://www.gutenberg.org/files/21051/21051-h/21051-h.htm  
> Thanks to redscudery, as always, for her beta services and for her general amazingness.  
> And thanks to you for reading, friends. xoxoxoxox


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